1. Field of the Invention
The present invention generally relates to liquid crystal display (LCD), and more particularly to gate driving waveform control for double gate LCD.
2. Description of the Prior Art
A liquid crystal display (LCD) typically includes rows and columns of picture elements (or pixels) arranged in matrix form. Each pixel includes a thin film transistor (TFT) and a pixel electrode formed on a substrate (or panel). The gates of the TFTs in the same row are connected together through a gate line, and controlled by a gate driver (or scan driver). The sources of the TFTs in the same column are connected together through a source line, and controlled by a source driver (or data driver). A common electrode is formed on another substrate (or panel). A liquid crystal (LC) layer is sealed between the pixel electrode substrate and the common electrode substrate, and the voltage difference between the pixel electrode and the common electrode determines the display of the pixels.
The gate driver and the source driver are formed with a number of driving integrated circuit (IC) chips, respectively. As the source driving IC chip typically has cost higher than the gate driving IC chip, it is thus advantageous to reduce the number of the source driving IC chips in the LCD, even to increase the number of the gate driving IC chips. Accordingly, some double (or dual) gate LCD structures are disclosed, in which the number of the source lines (and the source driving IC chips) is reduced in half, while the number of the gate lines (and the gate driving IC chips) is doubled. As a whole the double gate LCD generally costs less than the conventional LCD. In the operation of the double gate LCD, the TFTs in the same line are turn on in turn, rather than at the same time as in the conventional LCD, during a cycle of horizontal scan (usually abbreviated as 1H).
As a result, nevertheless, the timing controller (or T-con) has to provide the gate driver clock signals that have the frequency two times the clock frequency of a conventional non-double gate LCD. The high frequency disadvantageously associates with complex circuitry, large circuit area and high cost. For the foregoing reason, a need has arisen to propose a novel gate driving waveform control for the double gate LCD which benefits with the double gate LCD without increasing complexity, area and cost in circuitry.